TWI844724B - Polyolefin adhesive composition - Google Patents

Abstract

The subject of the present invention is to provide an adhesive composition having high adhesion to non-polar resin substrates such as liquid crystal polymers and metal substrates, solder heat resistance, low dielectric properties, and excellent shelf life performance. An adhesive composition contains an acid-modified polyolefin (A) that satisfies the following (1) to (3), and contains one or more selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2), and a carbodiimide compound (B3). (1) Acid value is 5-50 mgKOH/g; (2) The bonding ratio (molar ratio) of carboxylic anhydride group to dicarboxylic acid group is 100/0-50/50; (3) When the total acid component bonded to the acid-modified polyolefin (A) is 100 mol%, the total amount of carboxylic anhydride group and dicarboxylic acid group is 90 mol% or more.

Description

Polyolefin adhesive composition

The present invention relates to a polyolefin adhesive composition. More specifically, it relates to a polyolefin adhesive composition used for bonding a resin substrate to a resin substrate or a resin substrate to a metal substrate. In particular, it relates to an adhesive composition for a flexible printed wiring board (hereinafter referred to as FPC), and a cover film, a laminate, a copper foil with a resin, and a bonding sheet containing the adhesive composition.

Flexible printed circuit boards (FPCs) have excellent flexibility, so they can cope with the multifunctionality and miniaturization of personal computers (PCs) and smart phones, and are therefore often used to assemble electronic circuit boards into narrow and complex interiors. In recent years, electronic equipment has been miniaturized, lightweight, high-density, and high-output. Due to these trends, the performance requirements for wiring boards (electronic circuit boards) have been increasing. In particular, with the high-speed transmission of signals in FPCs, the high-frequency signals have been progressing. Accompanying this, the requirements for low-dielectric properties (low dielectric constant, low dielectric loss tangent) in the high-frequency region of FPCs have become higher. In order to achieve such low-dielectric properties, strategies have been implemented to reduce the dielectric loss of the FPC base material and adhesive. As for adhesives, a combination of an acid-modified polyolefin and an epoxy resin (Patent Document 1), a combination of an acid-modified polyolefin and a polyfunctional isocyanate compound (Patent Document 2), a thermosetting adhesive composition containing an acid-modified polyolefin, a carbodiimide resin, a polyfunctional epoxy resin, and a filler (Patent Document 3), etc. have been developed. [Prior Art Documents] [Patent Documents]

[Patent Document 1] WO2016/047289 [Patent Document 2] WO2015/046378 [Patent Document 3] Japanese Patent Application No. 2019-127501

[The problem that the invention wants to solve]

However, it is known that polyolefin modified with maleic anhydride has carboxylic anhydride groups when it is first produced, but there is a problem that it absorbs moisture over time and the carboxylic anhydride ring opens. Therefore, it is known that if it is used without taking any measures to prevent moisture absorption as in Patent Document 1, the adhesion, solder heat resistance, dielectric properties (relative dielectric constant, dielectric loss tangent) and pot life performance will be insufficient.

As a result of intensive research to solve the above-mentioned problems, the present invention has been found that an adhesive composition containing an acid-modified polyolefin having a predetermined ratio of carboxylic anhydride groups and containing at least one selected from the group consisting of an epoxy resin, an isocyanate compound and a carbodiimide compound exhibits excellent adhesion to a resin substrate and a metal substrate, solder heat resistance, and low dielectric properties (relative dielectric constant, dielectric loss tangent), and has excellent performance in the pot life after being mixed with a hardener, thereby completing the present invention.

That is, the present invention aims to provide an adhesive composition that has good adhesion not only to polyimide (PI) but also to various resin substrates such as liquid crystal polymer (LCP) and metal substrates, and also has excellent solder heat resistance, dielectric properties, and shelf life performance. [Means for solving the problem]

An adhesive composition comprises an acid-modified polyolefin (A) satisfying the following (1) to (3), and at least one selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2) and a carbodiimide compound (B3). (1) The acid value is 5 to 50 mgKOH/g; (2) The bonding ratio (molar ratio) of the carboxylic acid anhydride group represented by formula (a1) to the carboxylic acid group represented by formula (a2) is (a1)/(a2) = 100/0 to 50/50; (3) When the total acid component bonded to the acid-modified polyolefin (A) is 100 mol%, the total amount of formula (a1) and formula (a2) is 90 mol% or more; [Chemical 1] [Chemistry 2] In formula (a1) and formula (a2), * represents an atomic bond to the acid-modified polyolefin (A).

The epoxy resin (B1) preferably includes a glycidylamine epoxy resin (B11), and is preferably a mixture of a glycidylamine epoxy resin (B11) and one or more selected from the group consisting of a glycidyl ether resin (B12) and an alicyclic epoxy resin (B13).

The isocyanate compound (B2) is preferably a polyfunctional isocyanate compound.

The carbodiimide compound (B3) is preferably a polyfunctional carbodiimide compound.

It is preferred that the composition further contains oligomeric polyphenylene ether (C), and more preferably contains an organic solvent.

An adhesive composition having a relative dielectric constant (ε _c ) of 3.0 or less and a dielectric loss tangent (tan δ) of 0.02 or less at 1 GHz. An adhesive sheet or laminate containing the adhesive composition. A printed wiring board containing the laminate as a constituent element. A covering film containing the printed wiring board as a constituent element. [Effects of the invention]

The adhesive composition of the present invention has good adhesion not only to polyimide but also to various resin substrates such as liquid crystal polymer and metal substrates, and has excellent solder heat resistance, low dielectric properties and shelf life performance.

<Acid-modified polyolefin (A)> The acid-modified polyolefin (A) (hereinafter also referred to as component (A)) used in the present invention satisfies the following requirements (1) to (3).

<Requirement (1)> The acid value of the acid-modified polyolefin (A) should be 5 mgKOH/g or more from the viewpoint of solder heat resistance and adhesion to resin substrates and metal substrates. Considering good compatibility with epoxy resin (B1), isocyanate compound (B2) and carbodiimide compound (B3), excellent bonding strength, high crosslinking density and good solder heat resistance, it should be 6 mgKOH/g or more, more preferably 7 mgKOH/g or more, and even more preferably 8 mgKOH/g or more. The upper limit should be 50 mgKOH/g. Considering good adhesion and solder heat resistance, as well as good solution viscosity and stability, and excellent pot life performance, it is preferably 40 mgKOH/g or less, more preferably 30 mgKOH/g or less, and particularly preferably 20 mgKOH/g or less. If it is within the above range, the manufacturing efficiency can also be improved.

<Requirement (2)> The bonding ratio (molar ratio) of the carboxylic acid anhydride group represented by formula (a1) and the carboxylic acid group represented by formula (a2) must be formula (a1)/formula (a2) = 100/0 to 50/50. [Chemistry 2] In formula (a1) and formula (a2), * represents an atomic bond to the acid-modified polyolefin (A).

In terms of good adhesion, solder heat resistance and pot life performance, formula (a1) is preferably in excess of formula (a2). Formula (a1)/formula (a2)=less than 100/more than 0 to more than 50/less than 50 is preferred, more preferably 99/1 to 55/45, particularly preferably 97/3 to 60/40, particularly preferably 95/5 to 65/35, particularly preferably 93/7 to 70/30, and most preferably 91/9 to 75/25.

Although the acid-modified polyolefin (A) has a carboxylic acid anhydride group, the carboxylic acid anhydride group will be ring-opened to become a carboxylic acid group as it slowly absorbs moisture during the production, packaging, and storage of the acid-modified polyolefin. Therefore, in order to make the bonding ratio of the carboxylic acid anhydride group represented by formula (a1) to the carboxylic acid group represented by formula (a2) within the aforementioned range, it is preferable to perform a dehydration condensation reaction in an organic solvent such as toluene after the production of the acid-modified polyolefin (A), or to perform a dehydration condensation reaction at a high temperature without a solvent.

The bonding ratio (molar ratio) of formula (a1)/formula (a2) can be measured by IR. Specifically, a calibration curve can be prepared using anhydrous maleic acid (hereinafter also referred to as maleic anhydride) as a standard substance, and the absorbance of the carbonyl (C=O) bond from the carboxylic anhydride group (near 1780 cm ^-1 ) and the absorbance of the carbonyl (C=O) bond from the carboxylic acid group (near 1730 cm ^-1 ) can be used to determine the bonding ratio.

<Requirement (3)> When the total acid component bonded to the acid-modified polyolefin (A) is 100 mol%, the total amount of formula (1) and formula (2) must be 90 mol% or more. Considering the good adhesion, solder heat resistance and pot life performance, it is preferably 92 mol% or more, more preferably 95 mol% or more, particularly preferably 98 mol% or more, particularly preferably 99 mol% or more, and may also be 100 mol%.

The acid-modified polyolefin (A) is preferably obtained by grafting at least one of maleic acid and maleic anhydride onto a polyolefin resin. The polyolefin resin refers to a polymer having a hydrocarbon skeleton as a main component, such as a homopolymer of an olefin monomer such as ethylene, propylene, butylene, butadiene, isoprene, etc., or a copolymer with other monomers, and a hydrogenate, a halogenate, etc. of the obtained polymer. That is, the acid-modified polyolefin is preferably obtained by grafting at least one of maleic acid and maleic anhydride onto at least one of polyethylene, polypropylene, and propylene-α-olefin copolymer.

The propylene-α-olefin copolymer is obtained by copolymerizing α-olefin with propylene as the main component. As the α-olefin, for example, one or more of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate, etc. can be used. Among the α-olefins, ethylene and 1-butene are preferred, and 1-butene is more preferred. The ratio of the propylene component to the α-olefin component of the propylene-α-olefin copolymer is not limited, and the propylene component is preferably 50 mol% or more, and more preferably 70 mol% or more.

Examples of carboxylic acid components other than maleic acid and maleic anhydride include itaconic acid, liraconic acid and their anhydrides, acrylic acid, methacrylic acid, etc. Specific examples of the acid-modified polyolefin (A) include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer, etc. Such acid-modified polyolefins may be used alone or in combination of two or more. Among them, maleic anhydride-modified propylene-butene copolymer is preferred.

The number average molecular weight (Mn) of the acid-modified polyolefin (A) is preferably in the range of 10,000 to 50,000. It is more preferably in the range of 15,000 to 45,000, particularly preferably in the range of 20,000 to 40,000, and particularly preferably in the range of 22,000 to 38,000. When it is above the lower limit, the cohesion becomes good and excellent adhesion can be exhibited. In addition, when it is below the upper limit, the fluidity is excellent and the workability becomes good.

The weight average molecular weight (Mw) of the acid-modified polyolefin (A) is preferably in the range of 40,000 to 180,000. It is more preferably in the range of 50,000 to 160,000, particularly preferably in the range of 60,000 to 150,000, particularly preferably in the range of 70,000 to 140,000, and most preferably in the range of 80,000 to 130,000. When it is above the lower limit, the cohesion becomes good and excellent adhesion can be exhibited. In addition, when it is below the upper limit, the fluidity is excellent and the workability becomes good.

The acid-modified polyolefin (A) is preferably a crystalline acid-modified polyolefin. The term "crystalline" as used in the present invention means that the polyolefin exhibits a clear melting peak during the temperature increase from -100°C to 250°C at 20°C/min using a differential scanning calorimeter (DSC).

The melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50°C to 120°C. It is more preferably in the range of 60°C to 100°C, and most preferably in the range of 70°C to 90°C. When it is above the lower limit, the cohesion from the crystallization becomes good, and excellent adhesion and solder heat resistance can be exhibited. In addition, when it is below the upper limit, the solution stability and fluidity are excellent, and the workability during bonding becomes good.

The heat of fusion (ΔH) of the acid-modified polyolefin (A) is preferably in the range of 5 J/g to 60 J/g. It is more preferably in the range of 10 J/g to 50 J/g, and particularly preferably in the range of 20 J/g to 40 J/g. When it is above the lower limit, the cohesion from the crystallization becomes good, and excellent adhesion and solder heat resistance can be exhibited. Moreover, when it is below the upper limit, the solution stability and fluidity are excellent, and the workability during bonding becomes good.

The method for producing the acid-modified polyolefin (A) is not particularly limited, and examples thereof include free radical grafting reaction (i.e., a reaction in which a free radical substance is generated for a polymer that becomes a main chain, and the free radical substance is used as a polymerization starting point to cause an unsaturated carboxylic acid and anhydride to undergo graft polymerization).

The free radical generator is not particularly limited, and an organic peroxide is preferably used. The organic peroxide is not particularly limited, and examples thereof include: di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, diisopropylbenzene peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxytrimethylacetate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauryl peroxide and other peroxides; azonitriles such as azobisisobutylonitrile and azobisisopropionitrile, and the like.

<Epoxy resin (B1)> The epoxy resin (B1) (hereinafter also referred to as component (B1)) used in the present invention is not particularly limited as long as it has a glycidyl group in the molecule, but preferably has two or more glycidyl groups in the molecule.

The content of the epoxy resin (B1) is preferably 0.5 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A). In order to obtain a sufficient curing effect and exhibit excellent adhesion and solder heat resistance, it is more preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. In addition, in order to have excellent adhesion, solder heat resistance and pot life performance and excellent low dielectric properties, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

The epoxy equivalent of the epoxy resin (B1) is preferably 50 g/eq or more, more preferably 100 g/eq or more, and particularly preferably 150 g/eq or more. Also, it is preferably 400 g/eq or less, more preferably 350 g/eq or less, and particularly preferably 300 g/eq or less. When it is within the above range, excellent solder heat resistance can be exhibited.

The epoxy resin (B1) used in the present invention preferably contains a glycidylamine epoxy resin (B11) from the viewpoint of adhesion and solder heat resistance, and is preferably a mixture of one or more of the group consisting of a glycidylamine epoxy resin (B11), a glycidyl ether resin (B12), and an alicyclic epoxy resin (B13). In other words, it is preferably a mixture of (B11) and (B12), or a mixture of (B11) and (B13), or a mixture of (B11), (B12), and (B13).

<Epoxypropylamine type epoxy resin (B11)> Epoxypropylamine type epoxy resin (B11) is not particularly limited as long as it is an amine type epoxy resin having one or more epoxypropyl groups in one molecule. Preferably, the epoxy resin has two or more epoxypropyl groups in one molecule, more preferably, the epoxy resin has three or more epoxypropyl groups in one molecule, and even more preferably, the epoxy resin has four or more epoxypropyl groups in one molecule.

Furthermore, the epoxy resin (B11) of the glycidylamine type is preferred because its adhesiveness is further improved by using a compound represented by the following general formula (b1). [Chemical 3] In the general formula (b1), R is an aryl group which may have a substituent, preferably a phenyl group which may have a substituent. The substituent of the aforementioned aryl group is not particularly limited, and examples thereof include: an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, an amino group, a glycidyl group, a glycidylamino group, or a glycidyl ether group. X1 and X2 are each independently a linear alkylene group having 1 to 5 carbon atoms which may have a substituent, and the carbon number is preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less. The substituent of the aforementioned alkylene group is not particularly limited, and examples thereof include: an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an amino group. m is 1 or 2, and n is 1 or 2. Preferably, either m or n is 2, and more preferably, both m and n are 2.

Specific examples of the epoxy resin (B11) are not particularly limited, and examples thereof include: tetraglycol diamino diphenylmethane, triglycol p-aminophenol, tetraglycol bisamino methyl cyclohexanone, N,N,N',N'-tetraglycol propyl-m-xylene diamine and other epoxy resins. Among them, N,N,N',N'-tetraglycol propyl-m-xylene diamine is preferred. These epoxy resins (B11) may be used alone or in combination of two or more.

The blending amount of the epoxy propylamine type epoxy resin (B11) is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, particularly preferably 0.05 parts by mass or more, particularly preferably 0.08 parts by mass or more, and most preferably 0.1 parts by mass or more, relative to 100 parts by mass of the acid-modified polyolefin (A), in terms of exhibiting a catalytic effect, good adhesion and solder heat resistance. In addition, in terms of good performance during the pot life, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and most preferably 15 parts by mass or less.

<Glycidyl ether type epoxy resin (B12)> The glycidyl ether type epoxy resin (B12) is not particularly limited as long as it is an epoxy resin having a glycidyl ether group in the molecule. It is preferably an epoxy resin having two or more glycidyl groups in one epoxy resin molecule, and is particularly preferably an epoxy resin having two or more glycidyl groups in one epoxy resin molecule and containing no nitrogen atom.

The blending amount of the glycidyl ether type epoxy resin (B12) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, particularly preferably 3 parts by mass or more, particularly preferably 4 parts by mass or more, and most preferably 5 parts by mass or more, relative to 100 parts by mass of the acid-modified polyolefin (A). Furthermore, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, particularly preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and most preferably 12 parts by mass or less. By being within the above range, excellent adhesion and solder heat resistance can be exhibited.

Specific examples of the glycidyl ether type epoxy resin (B12) are not particularly limited, and examples thereof include phenol novolac type epoxy resin and cresol novolac type epoxy resin, which are preferred from the viewpoint of adhesion to metal substrates. These glycidyl ether type epoxy resins (B12) may be used alone or in combination of two or more.

<Alicyclic epoxy resin (B13)> The alicyclic epoxy resin (B13) is not particularly limited as long as it is an epoxy resin having an alicyclic skeleton in the molecule. It is preferably an alicyclic epoxy resin having two or more glyoxypropyl groups in one epoxy resin molecule, and is particularly preferably an alicyclic epoxy resin having two or more glyoxypropyl groups in one epoxy resin molecule.

The blending amount of the cycloaliphatic epoxy resin (B13) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, particularly preferably 3 parts by mass or more, particularly preferably 4 parts by mass or more, and most preferably 5 parts by mass or more, relative to 100 parts by mass of the acid-modified polyolefin (A). Furthermore, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, particularly preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and most preferably 12 parts by mass or less. By being within the above range, excellent adhesion and solder heat resistance can be exhibited.

Specific examples of the alicyclic epoxy resin (B13) are not particularly limited, and examples thereof include epoxy resins containing a dicyclopentadiene skeleton, glycidyl hexahydrophthalate, 3,4-epoxyhexylmethyl formate, etc. Among them, epoxy resins containing a dicyclopentadiene skeleton are preferred. These alicyclic epoxy resins (B13) may be used alone or in combination of two or more.

By using a glycidylamine epoxy resin (B11) and at least one selected from the group consisting of a glycidyl ether epoxy resin (B12) and an aliphatic epoxy resin (B13), excellent adhesion can be exhibited. That is, the glycidylamine epoxy resin (B11) has a reaction and curing effect with the acid-modified polyolefin (A), the glycidyl ether epoxy resin (B12) and/or the aliphatic epoxy resin (B13). In addition, the glycidylamine epoxy resin (B11) has a reaction and curing catalyst effect between the acid-modified polyolefin (A) and the glycidylamine epoxy resin (B11), between glycidylamine epoxy resins (B11), between glycidyl ether epoxy resins (B12), between aliphatic epoxy resins (B13), and between glycidylamine epoxy resin (B11) and glycidyl ether epoxy resin (B12) and/or aliphatic epoxy resin (B13). Therefore, it can exhibit excellent adhesion not only to polyimide but also to non-polar resin substrates such as liquid crystal polymers and metal substrates.

When the glycidylamine type epoxy resin (B11) and one or more selected from the group consisting of glycidyl ether type epoxy resin (B12) and epoxy type epoxy resin (B13) are used, the total content thereof is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 20 parts by mass based on 100 parts by mass of the acid-modified polyolefin (A), from the viewpoint of adhesion, solder heat resistance and pot life performance.

The content of the glycidylamine type epoxy resin (B11) is preferably 1 to 50% by mass of the total epoxy resin (B1), more preferably 2 to 30% by mass, and most preferably 3 to 10% by mass. When the content is above the lower limit, a catalytic effect is exhibited, and the adhesion and solder heat resistance are good. When the content is below the upper limit, the crosslinking reaction does not proceed excessively, so the rigidity is not too high and the adhesion becomes good. In addition, the crosslinking reaction does not proceed excessively during the storage of the solution of the adhesive composition, and the shelf life is also good.

The epoxy resin (B1) used in the present invention may also use other epoxy resins. For example, biphenyl epoxy resin, naphthalene epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, glycidyl dimer epoxy resin and other glycidyl epoxy resins, triglycidyl isocyanurate, epoxidized polybutadiene, epoxidized soybean oil and other alicyclic or aliphatic epoxides may be used. One type may be used alone, or two or more types may be used in combination.

<Isocyanate compound (B2)> The isocyanate compound (B2) (hereinafter also referred to as component (B2)) used in the present invention is preferably a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule. In addition, a compound derived from a polyfunctional isocyanate compound may also be used.

The content of the isocyanate compound (B2) is preferably 0.5 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A). In order to obtain a sufficient curing effect and exhibit excellent adhesion and solder heat resistance, it is more preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. In addition, in order to have excellent adhesion, solder heat resistance and pot life performance, and excellent low dielectric properties, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

The isocyanate compound (B2) may be any of an aromatic isocyanate compound, an alicyclic isocyanate compound or an aliphatic isocyanate compound, and these may be used alone or in combination of two or more. Among them, an aliphatic isocyanate compound is preferred, and an aliphatic diisocyanate compound is more preferred. Aromatic isocyanate compounds include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, 3,3'-biphenyl diisocyanate, 4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, etc. These compounds can be used alone or in combination of two or more. Among them, 3,3'-dimethyl-4,4'-biphenyl diisocyanate is preferred. Examples of the alicyclic isocyanate compounds include isophorone diisocyanate, norbornene diisocyanate, 1,2-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, etc. These compounds can be used alone or in combination of two or more. The aliphatic isocyanate compound can be any of linear or branched aliphatic isocyanates. The linear aliphatic diisocyanate compound is preferably used, and specifically, it includes 1,3-propane diisocyanate, 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,7-heptamethylene diisocyanate, 1,8-octamethylene diisocyanate, 1,9-nonamethylene diisocyanate, etc. These compounds may be used alone or in combination of two or more. Among them, 1,6-hexamethylene diisocyanate is preferred.

The isocyanate compound (B2) may be an isocyanurate, adduct, diurea, uretdione, or allophanate of the aforementioned isocyanate compound. These compounds may be used alone or in combination of two or more. Among them, an isocyanurate or diurea is preferred.

<Carbodiimide compound (B3)> The carbodiimide compound (B3) used in the present invention (hereinafter, also referred to as component (B3)) is preferably a polyfunctional carbodiimide compound having two or more carbodiimide groups in one molecule. By using the carbodiimide compound (B3), the carboxylic anhydride group of the acid-modified polyolefin reacts with the carbodiimide, thereby enhancing the interaction between the adhesive composition and the substrate, and improving the adhesion and solder heat resistance.

The content of the carbodiimide compound (B3) is preferably 0.5 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A). In order to obtain a sufficient curing effect and exhibit excellent adhesion and solder heat resistance, it is more preferably 1 part by mass or more, more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more. In addition, in order to have excellent adhesion, solder heat resistance and pot life performance, and excellent low dielectric properties, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, particularly preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

The carbodiimide compound (B3) may be any one of an aromatic carbodiimide compound, an alicyclic carbodiimide compound or an aliphatic carbodiimide compound, and these may be used alone or in combination of two or more. Examples of the aromatic carbodiimide compound include poly-m-phenylene carbodiimide, poly-p-phenylene carbodiimide, poly-m-phenylene carbodiimide, poly-(diisopropylphenylene carbodiimide), poly-(methyldiisopropylphenylene carbodiimide), poly-(4,4'-diphenylmethane carbodiimide) and the like. Examples of the alicyclic carbodiimide compound include poly-m-cyclohexylcarbodiimide, poly-p-cyclohexylcarbodiimide, poly-(4,4'-dicyclohexylmethanecarbodiimide, poly-(3,3'-dicyclohexylmethanecarbodiimide, etc. The aliphatic carbodiimide compound may be any of a linear or branched aliphatic carbodiimide compound. A linear aliphatic carbodiimide compound is preferred, and specifically, polymethylenecarbodiimide, polyethylenecarbodiimide, polypropylenecarbodiimide, polybutylenecarbodiimide, polypentamethylenecarbodiimide, polyhexamethylenecarbodiimide, etc. may be used alone or in combination of two or more. Among them, aromatic carbodiimide or alicyclic carbodiimide is preferred.

＜Oligomer Polyphenylene Ether (C)＞ By including oligomer polyphenylene ether (C) in the adhesive composition of the present invention, better solder heat resistance can be exhibited. The oligomer polyphenylene ether (C) used in the present invention (hereinafter, also referred to as component (C)) is not particularly limited, and is preferably a compound having a structural unit represented by the following general formula (c1) and/or a structural unit represented by the general formula (c2). [Chemistry 4]

In the general formula (c1), R ₁ , R ₂ , R ₃ , and R ₄ are preferably each independently a hydrogen atom, an alkyl group which may be substituted, an alkenyl group which may be substituted, an alkynyl group which may be substituted, an aryl group which may be substituted, an aralkyl group which may be substituted, or an alkoxy group which may be substituted. The "alkyl" of the alkyl group which may be substituted is, for example, a straight chain or branched chain alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. More specifically, it includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, etc., and it is more preferably methyl or ethyl. The "alkenyl" of the alkenyl group which may be substituted is, for example, vinyl, 1-propenyl, 2-propenyl, 3-butenyl, pentenyl, hexenyl, etc., and it is more preferably vinyl or 1-propenyl. The "alkynyl" of the alkynyl which may be substituted may include, for example, ethynyl, 1-propynyl, 2-propynyl (propargyl), 3-butynyl, pentynyl, hexynyl, etc., preferably ethynyl, 1-propynyl or 2-propynyl (propargyl). The "aryl" of the aryl which may be substituted may include, for example, phenyl, naphthyl, etc., preferably phenyl. The "aralkyl" of the aralkyl which may be substituted may include, for example, benzyl, phenethyl, 2-methylbenzyl, 4-methylbenzyl, α-methylbenzyl, 2-vinylphenethyl, 4-vinylphenethyl, etc., preferably benzyl. The "alkoxy" of the alkoxy which may be substituted may include, for example, a linear or branched alkoxy having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. For example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, etc. can be listed, and methoxy or ethoxy is more preferred. When the above-mentioned alkyl, aryl, alkenyl, alkynyl, aralkyl, and alkoxy groups are substituted, they may have one or more substituents. As such substituents, for example, halogen atoms (for example, fluorine atoms, chlorine atoms, bromine atoms), alkyl groups having 1 to 6 carbon atoms (for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl), aryl groups (for example, phenyl, naphthyl), alkenyl groups (for example, vinyl, 1-propenyl, 2-propenyl), alkynyl groups (for example, ethynyl, 1-propynyl, 2-propynyl), aralkyl groups (for example, benzyl, phenethyl), alkoxy groups (for example, methoxy, ethoxy), etc. can be listed. Among them, _R1 and _R4 are methyl groups, and _R2 and _R3 are preferably hydrogen groups.

[Chemistry 5] In the general formula (c2), R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are each independently a hydrogen atom, an alkyl group which may be substituted, an alkenyl group which may be substituted, an alkynyl group which may be substituted, an aryl group which may be substituted, an aralkyl group which may be substituted, or an alkoxy group which may be substituted. In addition, the definitions of each substituent are as described above. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, etc., preferably a methyl group. Among them, R ₁₃ , R ₁₄ , R ₁₇ and R ₁₈ are methyl groups, and R ₁₁ , R ₁₂ , R ₁₅ and R ₁₆ are preferably hydrogen groups. In addition, -A- is preferably a linear, branched or cyclic divalent alkyl group having 20 or less carbon atoms, or oxygen. The carbon atoms of A are preferably 1 to 15, and particularly preferably 2 to 10. In addition, as the divalent alkyl group of A, methylene, ethyl, n-propyl, n-butyl, cyclohexyl, phenylene and the like can be listed, among which phenylene is preferred. Oxygen is particularly preferred.

The oligomeric polyphenylene ether (C) may also be a modified oligomeric polyphenylene ether obtained by functionalizing part or all of the oligomeric polyphenylene ether with ethylenically unsaturated groups such as vinylbenzyl, epoxy, amine, hydroxyl, alkyl, carboxyl, and silyl. In addition, both ends preferably have hydroxyl, epoxy, or ethylenically unsaturated groups. Ethylenically unsaturated groups include: vinyl, allyl, methacrylic, propenyl, butenyl, hexenyl, octenyl and other alkenyl groups; cycloalkenyl groups such as cyclopentenyl and cyclohexenyl; alkenylaryl groups such as vinylbenzyl and vinylnaphthyl. In addition, both ends may have the same functional group or different functional groups. From the viewpoint of balancing the low dielectric loss tangent and the reduction of resin residue to a high degree of control, both ends are preferably hydroxyl groups or vinyl benzyl groups, and both ends are more preferably hydroxyl groups or vinyl benzyl groups.

The compound having the structural unit represented by the general formula (c1) is particularly preferably a compound of the general formula (c3). In the general formula (c3), n is preferably 3 or more, more preferably 5 or more, and is preferably 23 or less, more preferably 21 or less, and particularly preferably 19 or less.

Furthermore, the compound having the structural unit represented by the general formula (c2) is particularly preferably a compound of the general formula (c4). In the general formula (c4), n is preferably 2 or more, more preferably 4 or more, and is preferably 23 or less, more preferably 20 or less, and particularly preferably 18 or less.

The number average molecular weight of the oligomeric polyphenylene ether (C) is preferably 3000 or less, more preferably 2700 or less, and particularly preferably 2500 or less. Furthermore, the number average molecular weight of the oligomeric polyphenylene ether (C) is preferably 500 or more, and more preferably 700 or more. By setting the number average molecular weight of the oligomeric polyphenylene ether (C) to be above the lower limit, the flexibility of the obtained adhesive layer can be improved. On the other hand, by setting the number average molecular weight of the oligomeric polyphenylene ether (C) to be below the upper limit, the solubility in organic solvents can be improved.

The content of the oligomeric polyphenylene ether (C) is preferably 0.05 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A). In terms of exhibiting excellent solder heat resistance, it is more preferably 1 part by mass or more, and particularly preferably 5 parts by mass or more. Furthermore, it is preferably 200 parts by mass or less. In terms of exhibiting excellent adhesion and solder heat resistance, it is more preferably 150 parts by mass or less, particularly preferably 100 parts by mass or less, and particularly preferably 50 parts by mass or less.

<Adhesive composition> The adhesive composition of the present invention contains an acid-modified polyolefin (A) that meets the aforementioned specific requirements, and contains one or more components selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2) and a carbodiimide compound (B3), and preferably further contains the aforementioned oligomeric polyphenylene ether (C). The adhesive composition of the present invention has excellent adhesion not only to polyimide, but also to low-polarity resin substrates such as liquid crystal polymers and metal substrates, and can exhibit solder heat resistance, shelf life performance and electrical properties (low dielectric properties). That is, the adhesive coating film (adhesive layer) obtained by applying the adhesive composition to the substrate and curing it can exhibit excellent low dielectric constant properties.

The total amount of maleic acid and maleic anhydride contained in the adhesive composition is preferably 1% by mass or less. In view of good adhesion, solder heat resistance and pot life performance, it is more preferably 0.8% by mass or less, more preferably 0.6% by mass or less, and particularly preferably 0.4% by mass or less. The less the total amount of maleic anhydride and maleic acid, the better, but it can be 0.01% by mass or more in industry, and can also be 0.1% by mass or more.

The relative dielectric constant (ε _c ) of the adhesive composition of the present invention at a frequency of 1 GHz is preferably 3.0 or less, more preferably 2.6 or less, and particularly preferably 2.3 or less. The lower limit is not particularly limited, and is practically 2.0. Furthermore, the relative dielectric constant (ε _c ) in the entire frequency range of 1 GHz to 60 GHz is preferably 3.0 or less, more preferably 2.6 or less, and particularly preferably 2.3 or less.

The dielectric loss tangent (tanδ) of the adhesive composition of the present invention at a frequency of 1 GHz is preferably 0.02 or less. It is more preferably 0.01 or less, and particularly preferably 0.008 or less. The lower limit is not particularly limited, and is practically 0.0001. Furthermore, the dielectric loss tangent (tanδ) in the entire frequency range of 1 GHz to 60 GHz is preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.008 or less.

In the present invention, the relative dielectric constant (ε _c ) and the dielectric loss tangent (tan δ) can be measured as follows. That is, the adhesive composition is applied to the release substrate in such a manner that the thickness after drying becomes 25 μm, and dried at about 130° C. for about 3 minutes. Then, it is heat-treated at about 140° C. for about 4 hours to harden it, and the hardened adhesive composition layer (adhesive layer) is peeled off from the release film. The relative dielectric constant (ε _c ) and the dielectric loss tangent (tan δ) of the adhesive composition layer after peeling are measured at a frequency of 1 GHz. Specifically, the relative dielectric constant (ε _c ) and the dielectric loss tangent (tan δ) can be calculated from the measurement using the cavity resonator perturbation method.

<Organic solvent> The adhesive composition of the present invention may further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it can dissolve the acid-modified polyolefin (A), epoxy resin (B1), isocyanate compound (B2), carbodiimide compound (B3) and oligomeric polyphenylene ether (C). Specifically, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, and decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcohol solvents such as methanol, ethanol, isopropanol, butanol, pentanol, hexanol, propanediol, and phenol; acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isobutyl alcohol, and butyl alcohol. Ketone solvents such as phenone and acetophenone; celluloses such as methylcellulose and ethylcellulose; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, butyl formate; glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-isobutyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-isobutyl ether, triethylene glycol mono-n-butyl ether, tetraethylene glycol mono-n-butyl ether, etc., and one or more of them can be used. In particular, considering the working environment and dryness, methylcyclohexane and toluene are preferred.

The amount of the organic solvent relative to 100 parts by mass of the acid-modified olefin (A) is preferably in the range of 100 to 1000 parts by mass, more preferably in the range of 200 to 900 parts by mass, and most preferably in the range of 300 to 800 parts by mass. When the amount is above the lower limit, the liquid state and the pot life are good. When the amount is below the upper limit, it is advantageous in terms of manufacturing cost and transportation cost.

As for the organic solvent, from the viewpoint of the solution state and pot life performance of the adhesive composition, it is preferred to use a mixed solution of one or more solvents (D1) selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons, and one or more solvents (D2) selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents. The mixing ratio is preferably solvent (D1)/solvent (D2) = 50-97/50-3 (mass ratio), more preferably 55-95/45-5 (mass ratio), particularly preferably 60-90/40-10 (mass ratio), and particularly preferably 70-80/30-20 (mass ratio). When the solvent (D1) is within the above range, the adhesive composition has good solution state and pot life. In addition, the solvent (D2) is preferably an aromatic hydrocarbon or an alicyclic hydrocarbon, and the solvent (D1) is preferably a ketone solvent.

Furthermore, the adhesive composition of the present invention may contain other components as needed within the scope that does not impair the effects of the present invention. Specific examples of such components include flame retardants, adhesion agents, fillers, and silane coupling agents.

<Flame retardant> The adhesive composition of the present invention may also be mixed with a flame retardant as needed within the range that does not impair the effect of the present invention. Examples of flame retardants include bromine-based, phosphorus-based, nitrogen-based, and metal hydroxide compounds. Among them, phosphorus-based flame retardants are preferred, and phosphoric acid esters such as trimethyl phosphate, triphenyl phosphate, and tricresyl phosphate, phosphates such as aluminum hypophosphite, and phosphazenes, etc., which are well-known phosphorus-based flame retardants, can be used. These can be used alone or in any combination of two or more. When a flame retardant is contained, it is preferably contained in a range of 1 to 200 parts by mass, preferably in a range of 5 to 150 parts by mass, and most preferably in a range of 10 to 100 parts by mass, relative to a total of 100 parts by mass of components (A) to (C). When the content is at least the above lower limit, the flame retardancy is good, and when the content is at most the above upper limit, the adhesiveness, solder heat resistance, electrical characteristics, etc. are not deteriorated.

<Adhesive agent> The adhesive composition of the present invention may contain an adhesive agent as needed within the scope of not impairing the effect of the present invention. Examples of adhesive agents include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, styrene resins, and hydrogenated petroleum resins, and are used for the purpose of improving the adhesive strength. These may be used alone or in any combination of two or more. When the adhesion agent is contained, it is preferably contained in a range of 1 to 200 parts by mass, more preferably in a range of 5 to 150 parts by mass, and most preferably in a range of 10 to 100 parts by mass, relative to 100 parts by mass of the total of components (A) to (C). By being above the lower limit, the effect of the adhesion agent can be exerted. In addition, by being below the upper limit, the adhesion, solder heat resistance, electrical characteristics, etc. will not be reduced.

<Filler> In the adhesive composition of the present invention, fillers such as silica may be blended as needed within a range that does not impair the effects of the present invention. By blending silica, properties such as solder heat resistance are improved, which is very desirable. As for silica, hydrophobic silica and hydrophilic silica are generally known. Here, in consideration of imparting moisture absorption resistance, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc. is preferred. When silica is contained, its content is preferably in the range of 0.05 to 30 parts by mass relative to 100 parts by mass of the total of components (A) to (C). By being above the aforementioned lower limit, the effect of improving solder heat resistance can be exerted. Furthermore, by being below the above upper limit, poor dispersion of silicon dioxide does not occur, the solution viscosity is good, and workability is good. Furthermore, the adhesiveness does not decrease.

<Silane coupling agent> In the adhesive composition of the present invention, a silane coupling agent may be mixed as needed within the scope that does not impair the effect of the present invention. By mixing a silane coupling agent, the properties such as metal adhesion and solder heat resistance are improved, which is very ideal. The silane coupling agent is not particularly limited, and examples thereof include those having an unsaturated group, those having an epoxypropyl group, and those having an amino group. Among them, from the perspective of solder heat resistance, silane coupling agents having a glycidyl group such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane are particularly preferred. When a silane coupling agent is contained, its content is preferably in the range of 0.5 to 20 parts by mass relative to 100 parts by mass of the total of components (A) to (C). When the content is 0.5 parts by mass or more, excellent solder heat resistance is good. On the other hand, when the content is 20 parts by mass or less, solder heat resistance and adhesion are good.

<Laminated body> The laminated body of the present invention is formed by laminating an adhesive composition on a substrate (substrate/adhesive layer two-layer laminated body), or further laminating a substrate (substrate/adhesive layer/substrate three-layer laminated body). Here, the adhesive layer refers to the layer of the adhesive composition after applying the adhesive composition of the present invention to a substrate and drying it. The laminated body of the present invention can be obtained by applying the adhesive composition of the present invention to various substrates according to the conventional method and drying it, and further laminating it with other substrates.

<Substrate> In the present invention, the substrate is not particularly limited as long as it can be coated with the adhesive composition of the present invention and dried to form an adhesive layer, and examples thereof include resin substrates such as film-like resins, metal substrates such as metal plates and metal foils, and paper.

Examples of the resin substrate include polyester resins, polyamide resins, polyimide resins, polyamide imide resins, liquid crystal polymers, polyphenylene sulfide, para-polystyrene, polyolefin resins, and fluorine resins, etc. The resin substrate is preferably a film-like resin (hereinafter also referred to as a substrate film layer).

The metal substrate can use any known conductive material that can be used for the circuit board. Examples of the material include: various metals such as SUS, copper, aluminum, iron, steel, zinc, nickel, and their alloys, plated products, metals treated with other metals such as zinc or chromium compounds, etc. It is preferably a metal foil, and more preferably a copper foil. The thickness of the metal foil is not particularly limited, and is preferably 1 μm or more, preferably 3 μm or more, and particularly preferably 10 μm or more. In addition, it is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. When the thickness is too thin, it may be difficult for the circuit to obtain sufficient electrical performance. On the other hand, when the thickness is too thick, the processing efficiency during circuit manufacturing may be reduced. The metal foil is usually provided in a roll-like form. The shape of the metal foil used in manufacturing the printed wiring board of the present invention is not particularly limited. When a strip-shaped metal foil is used, its length is not particularly limited. Also, its width is not particularly limited, but is preferably about 250 to 500 cm.

Examples of paper include high-quality paper, kraft paper, paper rolls, and cellophane. Examples of composite materials include glass epoxy resins.

Considering the adhesion and durability with the adhesive composition, the substrate is preferably polyester resin, polyamide resin, polyimide resin, polyamide imide resin, liquid crystal polymer, polyphenylene sulfide, para-polystyrene, polyolefin resin, fluorine resin, SUS steel plate, copper foil, aluminum foil, or glass epoxy resin.

<Adhesive sheet> In the present invention, the adhesive sheet is formed by laminating the aforementioned laminate and the release substrate via an adhesive composition. The specific configuration can be listed as laminate/adhesive layer/release substrate, or release substrate/adhesive layer/laminated body/adhesive layer/release substrate. By laminating the release substrate, it can function as a protective layer for the substrate. In addition, by using the release substrate, the release substrate can be demolded from the adhesive sheet, and then the adhesive layer can be transferred to another substrate.

The adhesive sheet of the present invention can be obtained by applying the adhesive composition of the present invention to various laminated bodies according to the conventional method and drying. Furthermore, if a release substrate is attached to the adhesive layer after drying, it can be rolled up without causing transfer to the back of the substrate, and the workability is excellent. Moreover, since it is protected by the adhesive layer, it has excellent storage and is easy to use. Furthermore, after applying to the release substrate and drying, if another release substrate is attached as needed, the adhesive layer itself can also be transferred to other substrates.

<Release substrate> The release substrate is not particularly limited. For example, a coating layer of a filler such as clay, polyethylene, or polypropylene is provided on both sides of high-quality paper, kraft paper, paper roll, or cellophane, and a silicone-based, fluorine-based, or alkyd-based release agent is further applied on each of the coating layers. In addition, a release agent is applied to various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, propylene-α-olefin copolymer, and films such as polyethylene terephthalate. Due to the release force of the release substrate and the adhesive layer, and the adverse effects of silicone on electrical properties, it is better to use an alkyd release agent on both sides of high-quality paper after polypropylene filling, or to use an alkyd release agent on polyethylene terephthalate.

In addition, in the present invention, the method of coating the adhesive composition on the substrate is not particularly limited, and examples thereof include a notch wheel coater, a reverse roller coater, and the like. Alternatively, the adhesive layer may be provided directly or by transfer method on the rolled copper foil or polyimide film that is a constituent material of the printed wiring board as needed. The thickness of the adhesive layer after drying may be appropriately changed as needed, and is preferably in the range of 5 to 200 μm. If the thickness of the adhesive film is less than 5 μm, the bonding strength is insufficient. If it is greater than 200 μm, problems may arise such as insufficient drying, an increase in residual solvent, and swelling during pressing in the manufacture of the printed wiring board. The drying conditions are not particularly limited, and the residual solvent rate after drying is preferably less than 1% by mass. If the content exceeds 1% by mass, residual solvent may cause foaming and swelling during the pressing of printed wiring boards.

<Printed wiring board> The "printed wiring board" in the present invention includes a laminate formed by a metal foil forming a conductive circuit and a resin substrate as a constituent element. The printed wiring board can be manufactured, for example, by using a metal-clad laminate and utilizing a conventionally known method such as a subtractive method. It is a general term for so-called flexible printed circuits (FPCs), flat cables, and tape automated bonding (TAB) circuit boards, etc., in which a conductive circuit formed by a metal foil is partially or fully coated with a covering film, screen printing ink, etc. as needed.

The printed wiring board of the present invention may be any laminated structure that can be used as a printed wiring board. For example, it may be a printed wiring board composed of four layers of a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Also, for example, it may be a printed wiring board composed of five layers of a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

Furthermore, if necessary, two or three or more printed wiring boards may be stacked.

The adhesive composition of the present invention is suitable for use in various adhesive layers of printed wiring boards. In particular, when the adhesive composition of the present invention is used as an adhesive, it has high adhesion not only to the known polyimide, polyester film, copper foil constituting the printed wiring board, but also to low-polarity resin substrates such as LCP, and can obtain solder reflow resistance, and the adhesive layer itself has excellent low dielectric properties. Therefore, it is suitable as an adhesive composition used for covering films, laminates, copper foils with resins, and adhesive sheets.

In the printed wiring board of the present invention, any resin film that has been used as a substrate of a printed wiring board can be used as the substrate film. Examples of the resin of the substrate film include polyester resin, polyamide resin, polyimide resin, polyamide imide resin, liquid crystal polymer, polyphenylene sulfide, para-polystyrene, polyolefin resin, and fluorine resin. In particular, the present invention has excellent adhesion to low-polarity substrates such as liquid crystal polymer, polyphenylene sulfide, para-polystyrene, and polyolefin resin.

<Coating film> As for the covering film, any insulating film known as an insulating film for printed wiring boards can be used. For example, films made of various polymers such as polyimide, polyester, polyphenylene sulfide, polyether sulfide, polyether ether ketone, polyarylamide, polycarbonate, polyarylate, polyamide imide, liquid crystal polymer, para-polystyrene, and polyolefin resin can be used. More preferably, it is a polyimide film or a liquid crystal polymer film.

The printed wiring board of the present invention can be manufactured using any conventionally known process in addition to using the materials of each layer described above.

A preferred embodiment is a semi-finished product made by stacking adhesive layers on a covering film layer (hereinafter referred to as a "covering film side semi-finished product"). On the other hand, a semi-finished product is made by stacking metal foil layers on a substrate film layer to form a desired circuit pattern (hereinafter referred to as a "substrate film side 2-layer semi-finished product"), or a semi-finished product is made by stacking adhesive layers on a substrate film layer and stacking a metal foil layer thereon to form a desired circuit pattern (hereinafter referred to as a "substrate film side 3-layer semi-finished product") (hereinafter, the substrate film side 2-layer semi-finished product and the substrate film side 3-layer semi-finished product are collectively referred to as the "substrate film side semi-finished product"). By laminating the cover film side semi-finished product obtained in this way to the substrate film side semi-finished product, a 4-layer or 5-layer printed wiring board can be obtained.

The semi-finished product on the substrate film side can be obtained, for example, by a manufacturing method comprising the following steps: (A) coating the aforementioned metal foil with a solution of a resin to form a substrate film, and preliminarily drying the coating; and (B) heat-treating and drying the laminate of the metal foil obtained in (A) and the preliminarily dried coating (hereinafter referred to as "heat treatment-desolventizing step").

The circuit in the metal foil layer can be formed by a conventionally known method. An additive method or a subtractive method can be used. The subtractive method is preferred.

The obtained semi-finished product on the substrate film side can be directly used for bonding with the semi-finished product on the covering film side, or can be bonded with a release film for preservation and then used for bonding with the semi-finished product on the covering film side.

The semi-finished product on the side of the covering film can be manufactured, for example, by applying an adhesive on the covering film. If necessary, a crosslinking reaction can be performed in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-hardened.

The obtained semi-finished product on the covering film side can be directly used for bonding with the semi-finished product on the base film side, or can be bonded with a release film for preservation and then used for bonding with the semi-finished product on the base film side.

The semi-finished product on the substrate film side and the semi-finished product on the cover film side are stored in the form of rolls, for example, and then bonded together to form a printed wiring board. As for the bonding method, any method can be used, for example, lamination can be performed using pressing or rollers. In addition, the two can be bonded while heating by methods such as hot pressing or using a heated roller device.

In the case of a reinforcing material side semi-finished product that is soft and can be rolled up, such as a polyimide film, it is more ideal to apply an adhesive to the reinforcing material for manufacturing. In addition, in the case of a reinforcing plate that is hard and cannot be rolled up, such as a metal plate such as SUS, aluminum, or a plate obtained by curing glass fiber with epoxy resin, it is more ideal to transfer and apply an adhesive pre-applied on a demoulding substrate. In addition, a crosslinking reaction in the applied adhesive can be performed as needed. In a preferred embodiment, the adhesive layer is semi-cured.

The obtained semi-finished product on the side of the reinforcing material can be directly used for bonding to the back of the printed wiring board, or it can be stored by bonding a release film and then used for bonding to the semi-finished product on the side of the base film.

The semi-finished product on the substrate film side, the semi-finished product on the covering film side, and the semi-finished product on the reinforcing material side are all laminated bodies for printed wiring boards in the present invention.

<Example> The present invention is described in more detail below with reference to an example. However, the present invention is not limited to the example. The abbreviation "part" in the example and the comparative example represents a mass part.

(Physical property evaluation method)

(1) Acid value (mgKOH/g) The acid value (mgKOH/g) in the present invention is obtained by dissolving the acid-modified polyolefin in toluene and titrating it in a methanol solution of sodium methoxide using phenolphthalein as an indicator.

(2) Number average molecular weight (Mn), weight average molecular weight (Mw) The number average molecular weight in the present invention is the value measured by using a gel permeation chromatography (hereinafter referred to as GPC, standard material: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-802 + KF-804L + KF-806L, column temperature: 30°C, flow rate: 1.0 ml/min, detector: RI detector) manufactured by Shimadzu Corporation.

(3) Determination of melting point (Tm) and heat of fusion (ΔH) The melting point and heat of fusion in the present invention are measured by using a differential scanning calorimeter (hereinafter referred to as DSC, manufactured by TA Instrument Japan, Q-2000) to melt the resin at a rate of 20°C/min and cool it down to form a resin. The values are measured from the top temperature and area of the melting peak when the temperature is raised again to melt.

(4) Determination of the bonding ratio between the carboxylic anhydride group (a1) and the carboxylic acid group (a2) [Preparation of calibration curve solution] Accurately weigh 0.050±0.001 g of maleic anhydride, dissolve it in chloroform, and dilute to 50 ml to prepare a 1.000 g/l solution A. Dilute solution A by 2 times to prepare a 0.500 g/l solution B. Dilute solution B by 4 times to prepare a 0.125 g/l solution C. [Preparation of calibration curve] Using an infrared spectrophotometer (manufactured by Shimadzu Corporation, FT-IR8200PC), measure the absorption spectrum (Abs) in the order of blank solution (chloroform), solution C, solution B, and solution A. Read the maximum absorption intensity near 1780 cm ^-1 of each spectrum, take the maleic anhydride concentration on the vertical axis and the intensity on the horizontal axis to make a calibration curve, and calculate its slope (1/a). [Preparation and measurement of sample solution] Accurately weigh 0.50±0.01g of the sample (acid-modified polyolefin (A)), add 6.7ml of chloroform to dissolve it, and prepare a sample solution. Use an infrared spectrophotometer to measure the absorption spectrum (Abs) of the sample solution. Read the maximum absorption intensity near 1780cm ^-1 (carboxylic anhydride group (a1)) and 1730cm ^-1 (carboxylic acid group (a2)) of the absorption spectrum, and calculate the content (mmol/g) of (a1) and (a2) per 1g of resin from the calibration curve. [Calculation] Calculation formula 1: Carboxylic acid anhydride group (a1) content (mmol/g) = H1 × (1/a) / C ÷ 99 × 1000 Calculation formula 2: Carboxylic acid group (a2) content (mmol/g) = H2 × 2.08 × (1/a) / C ÷ 117 × 1000 H1: Maximum absorption intensity around 1780 cm ^-1 (Abs) H2: Maximum absorption intensity around 1730 cm ^-1 (Abs) 2.08: Conversion coefficient of maleic acid absorption replaced by maleic anhydride absorption 1/a: Slope of the calibration line C: Concentration of acid-modified polyolefin (A) in the sample solution (mass %)

(5) Determination of the total amount of (a1) and (a2) in the total acid components bonded to the acid-modified polyolefin (A) The molar ratio of the carboxylic anhydride group (a1), the carboxylic acid group ( ^a2 ) and other acids (acrylic acid, etc.) in the ^acid -modified polyolefin (A) was quantitatively determined using a 400 MHz 1 H-nuclear magnetic resonance spectrometer ( 1 H-NMR). Deuterated chloroform was used as the solvent.

(6) Peel strength (adhesion) The adhesive composition described below was applied to a 12.5 μm thick polyimide film (manufactured by Kaneka Corporation, APICAL (registered trademark)) or a 25 μm thick LCP film (manufactured by Kuraray Corporation, Vecstar (registered trademark)) so that the thickness after drying was 25 μm, and dried at 130°C for 3 minutes. The thus obtained adhesive film (stage B product) was bonded to a 18 μm thick rolled copper foil (manufactured by JX Metal Co., Ltd., BHY series). The bonding is carried out in such a way that the glossy surface of the rolled copper foil contacts the adhesive layer, and the bonding is achieved by pressing at 160°C and under a pressure of 40kgf/ ^cm2 for 30 seconds. Then, the foil is hardened by heat treatment at 140°C for 4 hours to obtain a sample for peel strength evaluation. The peel strength is measured by stretching the film at 25°C, performing a 90° peel test at a stretching speed of 50mm/min. This test indicates the bonding strength at room temperature. <Evaluation Criteria> ◎: 1.0N/mm or more ○: 0.8N/mm or more and less than 1.0N/mm △: 0.5N/mm or more and less than 0.8N/mm ×: less than 0.5N/mm

(7) Solder heat resistance Samples were prepared using the same method as above. Samples of 2.0 cm × 2.0 cm were aged at 23°C for 2 days and flowed in a molten solder bath at 280°C for 10 seconds to check for changes in appearance such as bulges. <Evaluation criteria> ◎: No bulges ○: Some bulges △: Many bulges ×: Bumps and discoloration

(8) Relative dielectric constant (ε _c ) and dielectric loss tangent (tan δ) The adhesive composition described below was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying and curing became 25 μm, and dried at 130°C for 3 minutes. After heat treatment at 140°C for 4 hours to cure it, the Teflon sheet was peeled off to obtain an adhesive resin sheet for testing. The obtained adhesive resin sheet for testing was cut into strip samples of 8 cm × 3 mm to obtain test samples. The relative dielectric constant (ε _c ) and dielectric loss tangent (tanδ) were measured using Network Analyzers (manufactured by Anritsu Corporation) using the cavity resonator perturbation method at a temperature of 23°C and a frequency of 1 GHz. The relative dielectric constant and dielectric loss tangent obtained were evaluated as follows. <Evaluation criteria for relative dielectric constant> ◎: 2.3 or less ○: More than 2.3 and less than 2.6 △: More than 2.6 and less than 3.0 ×: More than 3.0 <Evaluation criteria for dielectric loss tangent> ◎: 0.008 or less ○: More than 0.008 and less than 0.01 △: More than 0.01 and less than 0.02 ×: More than 0.02

(9) Shelf life performance Shelf life performance refers to the stability of a resin solution (varnish) prepared by mixing component (A), component (B), and, if necessary, component (C) with a mixed solvent of methylcyclohexane, methyl ethyl ketone, and toluene (methylcyclohexane/methyl ethyl ketone/toluene = 72/8/20 (v/v)) so that the solid content concentration becomes 20% by mass, just after mixing or after a certain period of time after mixing. Good shelf life performance means that the viscosity of the varnish increases little and can be stored for a long time; poor shelf life performance means that the viscosity of the varnish increases (thickening), and in severe cases, gelation occurs, making it difficult to apply to the substrate and unable to be stored for a long time. The varnish prepared according to the ratio in Table 2 was measured for dispersion viscosity at 25°C using a Brookfield viscometer (rotor No. 2, rotation speed 60 rpm) to determine the initial dispersion viscosity ηB0. Afterwards, the varnish was stored at 25°C for 7 days and the dispersion viscosity ηB was measured at 25°C. The varnish viscosity was calculated according to the following formula and evaluated as follows. Solution viscosity ratio = solution viscosity ηB/solution viscosity ηB0 <Evaluation criteria> ◎: 0.5 or more and less than 1.5 ○: 1.5 or more and less than 2.0 △: 2.0 or more and less than 3.0 ×: 3.0 or more, or viscosity measurement cannot be performed using gelation

(Acid-modified polyolefin (A)) Production Example 1 (Production of acid-modified polyolefins PO-1a and PO-1b) 100 parts by mass of propylene-butene copolymer ("Tafmer (registered trademark) XM7080" manufactured by Mitsui Chemicals, Inc.), 20 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide were mixed and reacted using a double-screw extruder with the maximum temperature of the cylinder set to 170°C. Afterwards, decompression and degassing were performed in an extruder to remove the residual unreacted products, and maleic anhydride-modified propylene-butene copolymer (PO-1a, acid value 25 mgKOH/g, number average molecular weight 25,000, weight average molecular weight 80,000, Tm75°C, △H30J/g, carboxylic acid anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 89/11, the total amount of (a1) and (a2) in all acid components 100 mol%) was obtained. Then, PO-1a was placed in a dryer at 30°C and RH70% for 1 week to obtain PO-1b. PO-1b is a carboxylic acid anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 15/85.

Preparation Example 2 (Preparation of acid-modified polyolefins PO-2a and PO-2b) The same procedure as in Preparation Example 1 was followed except that the amount of maleic anhydride added was changed to 25 parts by mass, thereby obtaining a maleic anhydride-modified propylene-butene copolymer (PO-2a, acid value 48 mgKOH/g, number average molecular weight 17,000, weight average molecular weight 50,000, Tm 75°C, ΔH 25 J/g, bonding ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) = 88/12, total amount of (a1) and (a2) in all acid components 100 mol%). Then, PO-2a was placed in a dryer at 30°C and RH 70% for 1 week to obtain PO-2b. PO-2b has a carboxylic acid anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 13/87.

Preparation Example 3 (Preparation of acid-modified polyolefins PO-3a and PO-3b) The same procedure as in Preparation Example 1 was followed except that the amount of maleic anhydride added was changed to 6 parts by mass, thereby obtaining a maleic anhydride-modified propylene-butene copolymer (PO-3a, acid value 7 mgKOH/g, number average molecular weight 35,000, weight average molecular weight 130,000, Tm 82°C, ΔH 25 J/g, carboxylic anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 90/10, total amount of (a1) and (a2) in all acid components 100 mol%). Then, PO-3a was placed in a dryer at 30°C and RH 70% for 1 week to obtain PO-3b. PO-3b has a carboxylic acid anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 17/83.

Preparation Example 4 (Preparation of acid-modified polyolefins PO-4a and PO-4b) The same procedure as in Preparation Example 1 was followed except that the amount of maleic anhydride added was changed to 30 parts by mass, thereby obtaining a maleic anhydride-modified propylene-butene copolymer (PO-4a, acid value 55 mgKOH/g, number average molecular weight 13,000, weight average molecular weight 40,000, Tm 70°C, ΔH 25 J/g, carboxylic anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 88/12, total amount of (a1) and (a2) in all acid components 100 mol%). Then, PO-4b was placed in a dryer at 30°C and RH 70% for 1 week to obtain PO-4b. In PO-4b, the bonding ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) is 12/88.

Preparation Example 5 (Preparation of acid-modified polyolefins PO-5a and PO-5b) The same procedure as in Preparation Example 1 was followed except that the amount of maleic anhydride added was changed to 2 parts by mass and the amount of di-tert-butyl peroxide was changed to 0.5 parts by mass, thereby obtaining a maleic anhydride-modified propylene-butene copolymer (PO-5a, acid value 3 mgKOH/g, number average molecular weight 60,000, weight average molecular weight 200,000, Tm 80°C, ΔH 25 J/g, bonding ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) = 90/10, total amount of (a1) and (a2) in all acid components 100 mol%). Then, PO-5a was placed in a dryer at 30°C and RH 70% for 1 week to obtain PO-5b. In PO-5b, the bonding ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) is 18/82.

Production Example 6 (Production of acid-modified polyolefin PO-6a) 100 parts by mass of propylene-butene copolymer ("Tafmer (registered trademark) XM7080" manufactured by Mitsui Chemicals Co., Ltd.), 20 parts by mass of maleic anhydride, 5 parts by mass of acrylic acid, and 6 parts by mass of di-tert-butyl peroxide were mixed and reacted using a double-screw extruder with the maximum temperature of the cylinder section set to 170°C. Afterwards, the product was decompressed and degassed in an extruder to remove the remaining unreacted products, and a maleic anhydride acrylic acid-modified propylene-butene copolymer (PO-6a, acid value 30 mgKOH/g, number average molecular weight 25,000, weight average molecular weight 80,000, Tm 75°C, △H 30 J/g, carboxylic anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 89/11, and the total amount of (a1) and (a2) in the total acid components was 70 mol%). Then, PO-6a was placed in a dryer at 30°C and RH 70% for 1 week to obtain PO-6b. PO-6b has a carboxylic anhydride group (a1)/carboxylic acid group bonding ratio (a2) = 14/86.

Preparation Example 1 (Cyclization reaction of acid-modified polyolefin PO-1c1) In a 4-necked flask equipped with a Dean-Stark apparatus and a stirrer, add 100 parts by mass of PO-1b and 500 parts by mass of toluene, and react under reflux for 5 hours. After cooling, inject into a container filled with a large amount of methyl ethyl ketone to precipitate the resin (PO-1c1). PO-1c1 has an acid value of 25 mgKOH/g, a number average molecular weight of 25,000, a weight average molecular weight of 80,000, Tm75℃, △H30J/g, a bonding ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) = 100/0, and a total amount of (a1) and (a2) in all acid components of 100 mol%.

Preparation Examples 2 to 9 (Cyclization reaction of acid-modified polyolefins PO-1c2 to PO-6c1) Preparation Examples 2 to 9 were carried out in the same manner as Preparation Example 1, except that the modifications were made as shown in Table 1. The physical properties are shown in Table 1.

Example 1 100 parts by mass of PO-1c1 as component (A), 0.1 parts by mass of B11-1, 8 parts by mass of B12-1 as component (B1), and 432 parts by mass (20% by mass based on solid content concentration) of an organic solvent (methylcyclohexane/methyl ethyl ketone/toluene = 72/8/20 (v/v)) were mixed to obtain an adhesive composition. The mixing amount, bonding strength, solder heat resistance, pot life performance, and electrical properties are shown in Table 2.

Examples 2 to 35, Comparative Examples 1 to 15 The blending amounts of components (A) to (C) were changed as shown in Tables 2 to 4, and Examples 2 to 35 and Comparative Examples 1 to 15 were implemented in the same manner as Example 1. The evaluation results of bonding strength, solder heat resistance, electrical properties, and pot life are shown in Tables 2 to 4. In addition, the organic solvent (methylcyclohexane/methyl ethyl ketone/toluene = 72/8/20 (v/v)) was adjusted so that the solid content concentration was 20 mass %.

[Table 1]

[Table 2]

[table 3]

[Table 4]

The epoxy resin (B1), isocyanate compound (B2), carbodiimide compound (B3), and oligomeric polyphenylene ether (C) used in Tables 2 to 4 are as follows. ＜Epoxy resin (B1)＞ ＜Epoxy amine type epoxy resin (B11)＞ B11-1: N,N,N’,N’-tetracyclyl-m-xylene diamine: TETRAD (registered trademark)-X (manufactured by Mitsubishi Gas Chemical Co., Ltd.) ＜Epoxy ether type epoxy resin (B12)＞ B12-1: Phenol novolac type epoxy resin Resin: jER (registered trademark) 152 (Mitsubishi Chemical Corporation) B12-2: o-cresol novolac type epoxy resin: YDCN-700-3 (Nippon Steel & Sumitomo Metal Chemical Corporation) <Epoxy resin (B13)> B13-1: Dicyclopentadiene type epoxy resin: HP-7200H (DIC Corporation epoxy equivalent 278g/eq) ＜Isocyanate compound (B2)＞ B21: Isocyanurate of hexamethylene diisocyanate: SUMIDUR (registered trademark) N-3300 (manufactured by Bayer AG) B22: Diurea of hexamethylene diisocyanate: DURANATE (registered trademark) 24A-100 (manufactured by Asahi Kasei Chemicals Co., Ltd.) ＜Carbodiimide compound (B3) > B31: Polyfunctional carbodiimide: CARBODILITE (registered trademark) V-09 (manufactured by Nisshinbo Chemical Co., Ltd.) B32: Polyfunctional carbodiimide: CARBODILITE (registered trademark) V-03 (manufactured by Nisshinbo Chemical Co., Ltd.) ＜Oligomer (C) > C1: Oligomer (polyphenylene ether styrene modified product: OPE-2St 2200 (Mn2000 compound with the structure of general formula (c4) manufactured by Mitsubishi Gas Chemical Co., Ltd.) C2: Oligomer (polyphenylene ether: SA90 (Mn1800 compound with the structure of general formula (c3) manufactured by SABIC)

As can be seen from Tables 2 to 4, in Examples 1 to 35, the adhesion, solder heat resistance, shelf life performance and dielectric properties are all good. On the other hand, in Comparative Examples 1, 6 and 11, the ratio of carboxylic anhydride group (a1)/carboxylic acid group (a2) is low, so the adhesion to the liquid crystal polymer and the copper foil, the solder heat resistance and the shelf life performance are reduced. In Comparative Examples 2, 7 and 12, the acid value of the acid-modified polyolefin (A) is high, so the solder heat resistance and the shelf life performance are reduced. In Comparative Examples 3, 8 and 13, the acid value of the acid-modified polyolefin (A) is low, so the adhesion to the liquid crystal polymer and the copper foil, and the solder heat resistance are reduced. In Comparative Examples 4, 9 and 14, the total amount of carboxylic anhydride group (a1) and carboxylic acid group (a2) is small, so the solder heat resistance and the shelf life performance are reduced. Comparative Examples 5, 10, and 15 do not contain any of the epoxy resin (B1), isocyanate compound (B2), and carbodiimide compound (B3), so the solder heat resistance is reduced. [Industrial Applicability]

The adhesive composition of the present invention has excellent adhesion not only to polyimide, but also to non-polar resin substrates such as liquid crystal polymers, and metal substrates such as copper foil. It also has excellent solder heat resistance and low dielectric properties, and its shelf life performance is also excellent. The adhesive composition of the present invention can obtain an adhesive sheet and a laminated body obtained by bonding using the adhesive sheet. Due to the above characteristics, it is useful in the use of flexible printed wiring boards, especially in FPC uses that require low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high frequency region.

without

Claims (11)

An adhesive composition comprises an acid-modified polyolefin (A) satisfying the following (1) to (3) and at least one selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2) and a carbodiimide compound (B3); the number average molecular weight (Mn) of the acid-modified polyolefin (A) is in the range of 10,000 to 50,000, and the weight average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 40,000 to 180,000; the epoxy resin (B1) has a glycidyl group in its molecule; the isocyanate compound (B2) has two or more carbodiimide groups in its molecule; The carbodiimide compound (B3) is a polyfunctional carbodiimide compound having two or more carbodiimide groups in one molecule; (1) the acid value is 5 to 50 mgKOH/g; (2) after production, the bonding ratio (molar ratio) of the carboxylic acid anhydride group represented by the formula (a1) and the carboxylic acid group represented by the formula (a2) after dehydration condensation reaction is formula (a1)/formula (a2) = 100/0 to 50/50; (3) when the total acid component bonded to the acid-modified polyolefin (A) is 100 mol%, the total amount of the formula (a1) and the formula (a2) is 90 mol% or more;

In formula (a1) and formula (a2), * represents an atomic bond to the acid-modified polyolefin (A). The adhesive composition of claim 1, wherein the epoxy resin (B1) comprises a glycidylamine epoxy resin (B11), and is a mixture of the glycidylamine epoxy resin (B11) and one or more selected from the group consisting of a glycidyl ether resin (B12) and an alicyclic epoxy resin (B13). As in the adhesive composition of claim 1, wherein the isocyanate compound (B2) is a multifunctional isocyanate compound. As in the adhesive composition of claim 1, wherein the carbodiimide compound (B3) is a multifunctional carbodiimide compound. The adhesive composition of any one of claim items 1 to 4 further contains oligomeric polyphenylene ether (C). If the adhesive composition of any one of claim items 1 to 4 further contains an organic solvent. The adhesive composition of any one of claims 1 to 4 has a relative dielectric constant (ε _c ) of less than 3.0 and a dielectric loss tangent (tan δ) of less than 0.02 at 1 GHz. An adhesive sheet containing an adhesive composition as described in any one of claims 1 to 7. A laminate containing an adhesive composition as described in any one of claims 1 to 7. A printed wiring board comprising a laminate as claimed in claim 9 as a constituent element. A covering film comprising a printed wiring board as claimed in claim 10 as a constituent element.